To understand the sentence "Who did the girl the teacher forced to talk complain to?" One must determine that "the girl" is to be taken as the missing subject of the verb "talk" and that "who" is the missing object of the preposition "to." Sentences with such long-distance dependencies as that between "the girl" and the subject position preceding "to talk" pose special problems for theories of sentence comprehension. They challenge the apparent human limits on short-term memory and processing capacity, in that arbitrary amounts of linguistic material can intervene between the items that are dependent upon each other and any one sentence can contain several long-distance dependencies. Further, they are subject to unique linguistic constraints that a language user must honor. We propose experiments to study the comprehension of sentences with long-distance dependencies, using reaction time and other measures of processing difficulty. Our goals are to determine what decision principles people follow in understanding such sentences, to identify the various types of information (lexical, pragmatic, suprasegmental, grammatical constraints) they use in making decisions about long-distance dependencies, and to specify the sequence in which they use functionally different types of information.